东江流域河流碳硅耦合特征及其控制机制  

Characteristics and mechanism controlling on the coupling of carbon and silicon biogeochemical cycles in the Dongjiang River,Pearl River Basin

作　　者：张超 韦刚健[1,2] 刘熙[1,2] 叶丰 黄龙[1,2] 崔灏[1,2,3] 张卓盈 罗仿 王利伟[1,2] ZHANG Chao;WEI Gangjian;LIU Xi;YE Feng;HUANG Long;CUI Hao;ZHANG Zhuoying;LUO Fang;WANG Liwei(State Key Laboratory of Deep Earth Processes and Resources,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;CAS Center for Excellence in Deep Earth Science,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州地球化学研究所,深地过程与战略矿产资源全国重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球化学》2025年第2期177-187,共11页Geochimica

基　　金：国家重点研发计划项目(2022YFF0800501);国家自然科学基金项目(41991325)联合资助。

摘　　要：开展淡水体系生物地球化学循环过程的碳硅耦合研究有助于更好理解陆地–河流–海洋的生源要素循环过程。近年来,淡水体系碳硅耦合过程的研究主要以天然湖泊或水库为主,针对流速更快、水体驻留时间更短、具有更多陆源物质直接输入的河流生态系统的研究偏少,其碳硅耦合过程的影响因素及控制机制尚不清晰。本研究选择华南东江流域,开展不同季节溶解无机碳(DIC)、C同位素组成(δ^(13)C_(DIC))和溶解硅(DSi)的观测,发现流域内碳酸盐类矿物化学风化及土壤CO_(2)输入是影响河水δ^(13)C_(DIC)值的重要因素。水生生物,特别是浮游植物光合作用及汛期陆源DIC的输入也可能影响河水δ^(13)C_(DIC)值。东江河水碳硅耦合过程主要受流域硅酸盐类矿物化学风化和水生生物活动影响,尤其是“生物泵”作用能有机耦合碳硅循环过程,该作用与温度和大气降水等气候因素密切相关。上述认识有助于更全面了解淡水生态系统的碳硅耦合过程,更好评估其对全球碳循环的贡献。The study of the coupling of carbon and silicon biogeochemical cycles in freshwater systems will improve our understanding of the biogeochemical cycles of land,rivers,and oceans.In recent years,studies on carbon-silicon(C-Si)coupling processes in freshwater systems have mainly focused on natural lakes or reservoirs,while studies on river ecosystems with faster flow rates,shorter residence times,and more direct input of terrigenous materials are scarce,resulting in a lack of knowledge on the mechanism for the C-Si coupling in river systems.In this study,observations on dissolved inorganic carbon(DIC),its carbon isotopic composition(δ^(13)C_(DIC)),and dissolved silicon(DSi)were performed in a series of stations covering the whole basin of the Dongjiang River in South China in both the dry and wet seasons.The results show that the export from the chemical weathering of carbonate minerals and CO_(2)input from soils are the most important factors affecting δ^(13)C_(DIC) of the river water.The photosynthesis of aquatic organisms,especially phytoplankton,and the input of terrigenous DIC during the wet season may also influence δ^(13)C_(DIC) in the river water.The C-Si coupling process in the Dongjiang River is mainly influenced by the chemical weathering of the silicate minerals in the basin,which are largely enhanced by the warm and wet climate.Moreover,the‘biological pump’of the aquatic ecosystem organically coupled the C-Si cycle processes in the river system,which is closely associated with temperature and atmospheric precipitation.These findings will help to provide a comprehensive understanding on carbon-silicon coupling processes in river systems,which may contribute to the evaluation of their contribution to the global carbon cycle.

关 键 词：溶解无机碳 碳同位素 碳硅耦合 东江流域 

分 类 号：P343.1[天文地球—水文科学] P593[天文地球—地球物理学]